Biomedical subjects
Publications and source records attributed to T Takashima.
We report a case of segmental hepatic iron deposition in the parenchyma peripheral to a tumor-thrombosed intrahepatic portal vein. On MR imaging, especially fast low-angle shot image, the liver parenchyma was demonstrated as a hypointense area with segmental and wedge-shaped configuration. Absence of portal blood flow may cause such segmental hepatic iron deposition.
We report a histological analysis of the areas of high density in the postequilibrium and delayed phase CT in 43 focal hepatic lesions. The cases consisted of 16 cholangiocellular carcinomas, 9 hepatocellular carcinomas (including a sclerosing type of hepatocellular carcinoma and a combined hepatocellular-cholangiocellular carcinoma), 13 metastases, 2 granulomas, an inflammatory pseudotumor, a malignant lymphoma, and an epithelioid hemangioendothelioma. Computed tomography was performed after hepatic angiography using 40-50 g iodine and arteriographic CT using 35 g iodine. The areas of delayed enhancement corresponded histologically to fibrotic tissues, from inflammatory change to extensive fibrosis.
OBJECTIVE: The enhancement of ascites following intravenous administration of Gd-DTPA on MRI was investigated. MATERIALS AND METHODS: Magnetic resonance imaging was performed in 20 patients with ascites (8 peritoneal carcinomatosis, 2 tuberculous peritonitis, 8 liver cirrhosis, 1 nephrotic syndrome, 1 peritoneal adhesion), and T1-weighted SE images were obtained before and 15-20 min following intravenous administration of Gd-DTPA (0.1 mmol/kg). RESULTS: There were 10 exudative ascites and 10 transudative ascites. Eight of 10 exudative ascites showed enhancement, in contrast to none of 10 transudative ascites. The precontrast signal intensity ratios (SIRs) of exudative ascites were significantly higher (p < 0.05) than those of transudative ascites, and the postcontrast SIRs of exudative ascites were significantly higher (p < 0.01) than those of transudative ascites. This difference was thought to be caused by increased peritoneal permeability and higher protein concentration in the cases with exudative ascites in this study. CONCLUSION: It is concluded that enhancement of ascites on MRI obtained 15-20 min after intravenous administration of Gd-DTPA is not an uncommon finding in exudative ascites (especially associated with peritoneal carcinomatosis).
OBJECTIVE: We report the imaging features of hepatic peribiliary cysts (PC) and the course of their development on CT. MATERIALS AND METHODS: Both CT and US findings were correlated with histopathologic findings in two patients with PC at autopsy. Five patients with cysts around the portal vein on CT but without histologic correlation were also included in this study. In six patients the course of PC development was observed. RESULTS: In the two autopsy cases cystic dilatation of the peribiliary glands was confirmed. The cases showed continuous small cysts along the portal veins reflecting the periportal collar seen on CT and the abnormal MR signal intensity of the periportal area. Ultrasound (US) showed round or tubular anechoic lesions around the large portal tracts mimicking dilatation of the bile ducts. Clustered cysts and echogenic dots or bands around PC were also seen. In three of six cases the PCs gradually enlarged and increased in number. CONCLUSION: In patients with liver cirrhosis PCs can be demonstrated by CT, US, and MRI in the vicinity of the hepatic hilum. Peribiliary cysts enlarge gradually and must be differentiated from dilatation of bile ducts or edema of portal tracts.
OBJECTIVE: The purpose of this study is to demonstrate the relation between focal hepatic fatty infiltration and aberrant gastric venous drainage (AGVD) in the posterior edge of the medial segment (PEMS) of the liver. MATERIALS AND METHODS: We present two cases of focal hepatic fatty infiltration with AGVD in the PEMS and discuss their imaging features. RESULTS: In both cases the focal fatty infiltration areas were hyperechoic on sonography, hypodense on CT, and hyperintense on T1-weighted MRI. Computed tomography during arterial portography (CTAP) showed nodular perfusion defects corresponding to the areas in both cases, and early enhancement of the area was observed with dynamic MRI in one case. Although the findings on CTAP and dynamic MRI suggested a neoplastic nature for the lesions, focal fatty infiltration was confirmed with surgical resection in one case and with imaging follow-up in the other. Aberrant gastric venous drainage into the area was demonstrated on arteriography in both cases. CONCLUSION: The variation in blood supply caused by AGVD may play an important role in fatty metabolism in the PEMS of the liver and may influence imaging features.
OBJECTIVE: To demonstrate the imaging findings seen in two cases of mucinous type of cholangiocellular carcinoma of the liver. MATERIALS AND METHODS: The CT and MR findings of two patients with pathologically proven mucinous type of cholangiocellular carcinoma were analyzed. RESULTS: One of them showed calcification, both cases had no enhancing on the arterial dominant phase of dynamic CT, but showed enhancement in the periphery and internal septations on the equilibrium phase. The internal signal intensity was homogenous, and extremely hypo- and hyperintense on T1- and T2-weighted images, respectively. CONCLUSION: Imaging findings were unique reflecting the characteristic pathological features that cancer cell nests are suspended in a large mucinous lake, and the specific diagnosis was considered to be possible by the integrated imaging diagnosis.
PURPOSE: The purpose of our study was to assess the efficacy of single-level dynamic CT during hepatic arteriography (D-CTA) in the differentiation between hypervascular hepatocellular carcinoma (HCC) and hypervascular pseudolesion. METHOD: D-CTA was performed in nine cases with HCC and nine cases with pseudolesion. Findings on D-CTA were retrospectively analyzed. RESULTS: The transition of the stain of pseudolesion on D-CTA was divided into three phases: (1) inflow of the contrast material into the portal vein within the lesion, (2) lesion staining, and (3) fading out of the stain; that of HCC was divided into four phases: (1) inflow of CM into tumor, (2) tumor staining, (3) inflow of CM into the adjacent liver, and (4) coronal stain of adjacent liver. The coronal stain was seen in all HCCs but not in any pseudolesions. CONCLUSION: The present study suggest that D-CTA is a helpful option in the differentiation between HCC and pseudolesion.
PURPOSE: The goal of our study was to assess the prevalence of pseudolesion in segment IV of the liver on MRI in patients with and without liver cirrhosis. METHOD: Patients were divided into three groups: 10 patients with angiographically confirmed aberrant gastric venous drainage and liver cirrhosis (Group 1), 250 consecutively selected patients with liver cirrhosis (Group 2), and 250 with normal liver (Group 3). The signal intensity of pseudolesion in segment IV on T1- and T2-weighted MRI in the 510 patients was analyzed. RESULTS: In Group 1, five pseudolesions were visible and hyperintense on T1-weighted images. On T2-weighted images, four were visible and hypointense. In Group 2, 11 were seen (4.4%). All were hyperintense on T1-weighted images. Five were hypointense on T2-weighted images. In Group 3, one pseudolesion was seen (0.4%). CONCLUSION: The prevalence of pseudolesion in segment IV on MRI is higher in liver cirrhosis than in normal liver. The lesion is hyperintense on T1-weighted images when visible.
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The glomangioma is a hyperplastic lesion of the glomus body. This uncommon tumor is seldom located in the nasal cavity or paranasal sinuses. We present what is to our knowledge the eleventh documented case of an intranasal glomangioma. The differential diagnosis of this lesion, its symptoms, pathogenesis and therapy are discussed. Complete excision is normally curative for this tumor.
Postmortem perfusion studies were carried out following hepatic artery embolization (HAE) with Gelfoam powder in rats (n = 17) and rabbits (n = 10). The inflow of barium particles into the hepatic arteries after portal vein injection (porto-arterial shunt: P-A shunt) was analyzed by stereomicroscopic and histologic examinations. A P-A shunt was observed in 12 of 17 rats (71%) following HAE (embolization group). The difference in occurrence rates of P-A shunt between control (1/12 = 9.2%) and embolization groups was statistically significant (chi 2, p less than 0.01) in rats. In rabbits, a P-A shunt was seen in only one of 10 animals in the embolization group. P-A shunting may have an important role in reconstructing the blood supply to hepatic tumors after HAE, and administration of anticancer drugs via the portal vein following HAE might be effective. However, the differences among different species of animals should be considered before clinical application.
A 47-year-old woman with branch retinal arterial occlusion treated with sodium ozagrel is described. The patient presented with acute visual field loss in her right eye. Blood tests demonstrated the elevation of beta-thromboglobulin and platelet factor 4. Sodium ozagrel, a thromboxane A2 synthetase inhibitor, 160 mg daily was administered for 14 days. This treatment prevented exacerbation of retinal arterial thrombosis and produced a marked improvement in the visual field loss. Sodium ozagrel may be a useful drug in the treatment of acute retinal arterial occlusion thought to be caused by thrombosis.
The purpose of this communication is to present a case of resection performed for local recurrent tumors of primary malignant melanoma of the esophagus (PMME) and to review the relevant literature. The patient was a 54 year-old man who had received an intraabdominal esophagectomy with a total gastrectomy for primary malignant melanoma of the abdominal esophagus in another hospital, in November 1995. After the initial operation, he was treated as an outpatient. In August 1997, computed tomography and ultrasonography revealed recurrent tumors in the dorsal pancreatic lymph node and in the right adrenal gland. The recurrent tumor of the dorsal pancreas directly invaded the dorsal pancreas parenchyma and occluded the superior mesenteric vein and splenic vein, and the other metastatic tumor in the right adrenal gland existed in the absence of circumference invasion. Metastases of the PMME were confirmed in the dorsal pancreas, the superior mesenteric vein, splenic vein, and right adrenal gland, and were removed by a total pancreatectomy on October 7, 1997. By immunohistochemical staining, we found that the focal areas expressed S-100 protein and HMB-45 antibody. Currently (February 1998), the patient is alive and disease-free. PMME is an extremely rare tumor with a poor prognosis for survival. Only 2 cases of removal of recurrent tumors, including the present case, have been reported. The treatment of choice is surgical resection, even in cases of recurrence, because radiotherapy and/or chemotherapy have not been proven to be beneficial; however, they may play a palliative role if surgery is not possible.
A 25-year-old woman who underwent surgical removal of a right frontal meningeal mesenchymal chondrosarcoma in 1980 manifested abdominal pain and progressive anemia after a traffic accident in April 1997. CT disclosed a well-enhanced solid mass 2.5 cm in diameter with internal calcific deposits at the tail of the pancreas and a surrounding hematoma of 5.5 cm in diameter. Surgical resection revealed a ruptured metastatic mesenchymal chondrosarcoma of the pancreas.
The clonal expression of oncogene-induced transformation-associated cell surface antigens (TAAs) of a WFB rat fetus fibroblast was analyzed by developing mAbs to TAAs. We identified four TAAs. Two out of four TAAs seemed to be involved in the cytotoxicity by NK cells. One is an hsp-like molecule. These TAAs may play an important role in the antitumor surveillance mechanism by the host immune system. By clarifying the molecular characteristics, it would be possible to apply the genes encoding these molecules in the immunotherapy of cancer.
This report describes three patients whose cystic portions were filled with intravenously injected Gadolinium-DTPA. Four cystic portions showed contrast enhancement of the whole wall on early MR images and enhancement of the content on delayed MR images. Two cystic portions showed no enhancement of content. We speculate that the difference is based upon the composition of the cyst walls.
A total of 155 cases of hepatocellular carcinoma smaller than 3 cm in greatest diameter were studied, and the survival rates obtained with various treatment methods were calculated. Patients were divided into an operated group (72 cases), transcatheter arterial embolization (TAE) group (52 cases), percutaneous ethanol injection therapy (PEIT) group (five cases), and a miscellaneous group (26 cases) according to the treatment received. The miscellaneous group included intraarterial chemotherapy, systemic chemotherapy, and no therapy. The survival rates of the operated and TAE groups were significantly higher than those of the miscellaneous group, but the survival rates of the TAE group decreased after two years had passed, and TAE showed limited long-term survival. In the PEIT group, the survival rates after three years were higher than those of the TAE group. TAE is effective for inoperable small HCC, but the indications for PEIT should be considered actively.
Olfactory bulbs are easily detected on coronal T1-weighted MR images. They are situated almost symmetrically opposite either side of the lower end of the olfactory sulci, and, on sagittal images, they are observed as thin soft-tissue bands immediately beneath the frontal lobe base. On axial images they are shown as oval, paramedian structures of intermediate intensity. Visualization of the olfactory tract, however, is not always possible. Our study reveals that, on axial images, detection of the olfactory bulb depends on technical factors; we recommend a 256 x 256 matrix, a 3-mm-thick slice, and less than a 0.6-mm gap. Despite the lack of complete visualization of olfactory bulbs and tracts, MR may be effective in demonstrating diseases of these entities.